Nowadays when you walk into any electronics store you’ll find a number of dock connector accessories that can be attached to your iPhone/iPod. But what about accessories for the headphone port? You can connect a whole lot more than just headphones. Below the jump we’ll take a look a few handy accessories for the lonely (and often underutilized) headphone port.

Peavey’s AmpKit LiNK is an iPhone, iPod touch, and iPad audio interface for electric guitar, bass, keyboards, etc. Unlike IK Multimedia’s iRig, AmpKit Link has a mini battery-powered amp to eliminate feedback. You can plug in your guitar and turn your device into an amp/effects board/recorder. The AmpKit Link can be used with Peavey’s official guitar effects app (AmpKit) or most other processing, recording, or tuning apps.

The Square reader is a magstrip credit card reader that plugs into your iPad/iPhone/iPod touch and various Android phones. Swipe and charge anyone’s credit card on-the-go using Square’s official app and have it automatically transferred to your bank account! Unlike other credit card readers, this one won’t block your dock port, so you can keep your device plugged in and charged. The best part about it is that it’s free! All one needs to do is download Square’s software and they’ll send you a reader in the mail. I’ve had one for a while now and though I’ve only used it a couple of times, I like knowing I can take credit card payments whenever, wherever.

RyzMedia's My TV Remote device is a little IR blaster that works with RYZ media’s TV Remote app, turning your iPhone or iPod Touch into a universal remote. The app itself is a little lacking compared to the other remote apps out there (like the L5 Remote which connects via dock port), but like the Square reader, the IR blaster won’t block your charging port, so you can charge and surf at the same time.

Know any other cool headphone port accessories? Let us know in the comments!